<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .left{
            height: 100px;
            width: 100px;
            background-color: red;
            float: left;
        }
        .right{
            height: 100px;
            background-color: seagreen;
            margin-left: 100px;
        }
        .l{
            width: 100px;
            height: 100px;
            float: left;
            background-color: sienna;
        }
        .r{
            width: 100px;
            height: 100px;
            float: right;
            background-color: slateblue;
        }
        .m{
            height: 100px;
            background-color: tomato;
        }
        .an{
            animation: show 1s linear;
            position: relative;
        }
        h3{
            text-align: center;
        }
        .an::before,.an::after{
            content: '';
            display: inline-block;
            width: 10px;
            height: 10px;
            background-color: yellowgreen;
        }
        @keyframes show{
            0%{
                opacity: 0;
                top: -10px;
            }
            100%{
                opacity: 1;
                top: 0;
            }
        }
    </style>
</head>
<body>
    <div class="left"></div>
    <div class="right"></div>
    <div class="l">

    </div>
    <div class="r">

    </div>
    <div class="m">

    </div>
    <h3>
        <span class="an">
            下面是问答题
        </span>
    </h3>
    <h4>请使用js完成1-100的求和</h4>
    <textarea></textarea>
    <h4>请问，js有几种基本数据类型，并写出来</h4>
    <textarea></textarea>
    <h4>请说出下面代码的运行结果</h4>
    <code>
        var a = 10;</br>
        if(true){</br>
           &nbsp; var a = 20;</br>
        }</br>
        console.log(a)</br>
    </code>
    <label for="">输出:</label>
    <input type="text">
</body>
</html>